Personal audio devices have been used with increasing regularity in recent years, and people continue to use these devices with greater frequency during of their daily activities (e.g. during exercise sessions, while traveling, while working, while participate in online coursework, etc.). Indeed, headphones have become so commonplace that they are often offered as a complementary gift to patrons of certain venues (e.g. flights, gaming events, etc.). Consequently, engineering optimal headphone devices has become a robust and specialized field requiring advanced technologies to meet the design, aesthetic, and functional requirements of the various users of these devices, and the various activities for which they are used.
Headphones come in a variety of shapes and sizes. One type or category of headphones are referred to as earphones or earbuds. Earphones typically include two small speakers held within two separate, small enclosures configured to fit or rest directly within a user's ear. In many modern earphone devices, a housing portion of the earphone enclosure is meant to rest in or near the user's cavum conchae, while a tip portion of the earphone is designed to fit into an outer portion of the user's ear canal. The speaker is often configured to be held within the tip portion. Because the anatomy of each person's ear is unique, however, earphones that are mass produced do not always provide an adequate fit for each unique user's individual ear anatomy. User's with larger ears may find that the earphones fit to loosely, while user's with smaller ears may find that the earphones fit too snug. This may cause discomfort and irritation.
Many engineers and manufacturers have attempted to remedy this problem by designing and providing cushions in multiple sizes that can be attached to the tip of the earphone (e.g. typically two to three different sizes—small, medium, large—may be provided). However, while a larger cushion can always be designed to accommodate users with larger ears, the design of small cushions is limited by the size of the leading portion of the tip to which the cushion is attached (the part that is meant to be situated in the users ear canal when worn). Some designs eliminate the cushion entirely to further minimize the dimension of the tip in the user's ear, but these still suffer from similar structural limitations of the speaker component disposed therein (described in more detail below). Because of this, such devices remain inadequate for those users having ear canal dimensions much smaller than average.
Finding an adequate remedy to this problem is complicated by the structural limitations and performance requirements of earphone devices.
Structurally, an earphone generally has a plastic or metal enclosure made up of a housing and a tip extending from the housing. The enclosure includes several electronics, including at the very least a speaker component and appropriate wiring. Advanced earphone devices can further include BLUETOOTH wireless connectivity, and thus require the earphone enclosure to include additional electronic components (e.g. a battery, a circuit board, an amplifier, a channel equalizer, a wired or wireless receiver, or other audio-electronic circuitry). Earphone devices typically have a tip extending outward from the remainder of the housing, within which the speaker component is typically disposed, and upon which a silicone or foam cushion may be attached. In earphone devices that utilize such cushions, the size of the cushions that may be used with a particular set of earphones is necessarily limited by the size of the tip. Accordingly, for user's with small ears, decreasing the diameter or thickness dimension of the earbud tip (the part leading into the user's ear canal) is essential to optimizing the overall earphone performance these user's experience—whether cushions are utilized or not.
Noting that the ability to decrease the size of the tip is necessarily limited by the size of the components disposed within the tip (e.g. the speaker), some manufacturers have made other attempts to minimize the tip dimensions. For instance, as indicated above, some manufacturers have designed earphones that forego the cushion entirely, leaving the outer plastic shell of the tip to be the contact interface with the interior of the ear canal. However, even for these earphone devices, the same limitations presented by the speaker component housed within still come into play. That is, the ability to decrease the dimensions of the tip is limited by the size of the components disposed within.
With respect to performance, the capacity of the electronics within an earphones are limited by their size. Of course, the speakers in such earphone devices must be very small in order to fit within the small structure of the enclosure. A speaker functions by pushing and pulling air molecules to generate pockets of high and low pressure that the human eardrum is capable of detecting, and that the human brain is capable of interpreting as sound. As the size of speaker parts (e.g. voice coil, spider, cone, magnet) decrease, so does the speaker's capacity to push and pull air molecules to generate sound. In other words, smaller speakers generate less volume and produce narrower frequency ranges than larger speakers. To some degree, the lower capacity of small speakers can be alleviated by bringing the speaker in close proximity to the user's eardrum (e.g. placing the speaker in the tip portion of the earphone). Indeed, the practical utility of earphone devices depends on their being brought in close proximity with the user's ear drum. The closer the speaker is to a user's eardrum, the easier it is for the human eardrum to detect the pressure fluctuations. Moreover, the closer the speaker is to the user's eardrum, the less noise exists that can interfere with the already small pressure fluctuations. Because of this, and as indicated above, some earphone designs includes a speaker component that is situated at or near the tip of the earbud—the part actually inserted into the user's ear canal. However, as noted, because effective speakers can only be manufactured so small without losing their effectiveness, retaining the speaker at the very tip of the earphone (the portion closest to the user's eardrums when worn) necessarily limits the ability to minimize the dimensions of tip of the earphone for smaller users.
Some engineers have attempted to remedy this problem by designing earphones where the speaker component is moved completely out of the tip and into another portion of the housing so that the earphone tip may be made even smaller. Because the speaker is disposed in a larger portion of the enclosure, the speaker component itself may be made even larger so that it produces more sound. However, problems with this design still exist.
First, the problems highlighted above with regard to the proximity of the speaker component to the user's eardrum are still apparent. In particular, although larger speakers may be used, moving the speaker into the housing still increases distance between the user's eardrum and the speaker component, and thereby increases the effect of noise (i.e. unwanted interference signals) that does not benefit from the natural filtering features of the walls of the ear canal. Second, moving the speaker into the housing means less space for the other components disposed within the housing (e.g. batteries, receivers, channel equalizers, and other components) where space is already limited. For instance, further congesting the earbud housing space with the speaker component might mean having to reduce the size of the battery, which would consequently reduce the time a person can use the earbuds on a single charge. Third, and moreover, the use of larger speakers in earphone housing requires more power to be drawn from the battery that is powering them. So even if the battery size did not need to be reduced, the amount of time a user could operate the earphones on a single charge would be reduced because of the greater amount of power the larger speakers draw during operation. This is of particular concern in wireless earphones that run on a battery with an already limited capacity. Indeed, many other problems with this design exist.
In sum, on the one hand earphones that employ a speaker at the very tip of the earphone will often fit too tightly within a user's ear canal and cause discomfort during use, especially during extended use. In some instances, where the user's ear anatomy is much smaller than average, the inadequacy of the fit may render the earphones entirely unusable. On the other hand, earphones that employ larger speakers enclosed in the housing portion away from the earphone tip suffer from decreased sound quality and operational capacity (e.g. increased noise interference, decreased run-time on a single charge, etc.). The foregoing issues are estimated to affect nearly 10% of earphone users.
Accordingly, there is a long-felt need in this field to adequately resolve the weaknesses apparent in the present devices. Making an earphone tip small enough to accommodate very small ear canal's calls for—in presently earbud models—moving the speaker component out of the earbud tip and into the remainder of the earbud housing so that the tip size can be reduced. But, as discussed, moving the speaker component into the remainder of the housing moves speaker parts further from the user's eardrum, thereby reducing the overall sound quality as described above. Additionally, moving the speaker into the housing means less space for the other components disposed within the housing. This can be particularly problematic for wireless earbuds—which also house batteries, receivers, channel equalizers, and other components—where space within the housing is already limited. For instance, further congesting the earbud housing space with the speaker component might mean having to reduce the size of the battery, which would reduce the time a person can use the earbuds on a single charge.
This dilemma makes it challenging to design earphones that provide an adequate fit for users having small ear canal dimensions, but while still maintaining the sound quality and other advantages (described above) that come from situating the speaker component within the tip of the earbud device.